Summary:
Currently, transactions can fail even if there is no actual write conflict.  This is due to relying on only the memtables to check for write-conflicts.  Users have to tune memtable settings to try to avoid this, but it's hard to figure out exactly how to tune these settings.

With this diff, TransactionDB will use both memtables and SST files to determine if there are any write conflicts.  This relies on the fact that BlockBasedTable stores sequence numbers for all writes that happen after any open snapshot.  Also, D50295 is needed to prevent SingleDelete from disappearing writes (the TODOs in this test code will be fixed once the other diff is approved and merged).

Note that Optimistic transactions will still rely on tuning memtable settings as we do not want to read from SST while on the write thread.  Also, memtable settings can still be used to reduce how often TransactionDB needs to read SST files.

Test Plan: unit tests, db bench

Reviewers: rven, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb, yoshinorim

Differential Revision: https://reviews.facebook.net/D50475

Summary: Fixed the valgrind error in ColumnFamilyTest::CreateAndDropRace

Test Plan: valgrind --error-exitcode=2 --leak-check=full ./column_family_test

Reviewers: kradhakrishnan, rven, anthony, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51795

Summary: For Transactions, we want to start using the SST files to do write conflict checking.  To do this, we need to make sure that compaction never removes all writes if an earlier snapshot exists.  So I had to change the way we process SingleDeletes to sometimes leave a SingleDelete behind when we encounter a Put followed by a SingleDelete.  See the comments in this diff for a more detailed explanation.

Test Plan: added more unit tests

Reviewers: rven, igor, kradhakrishnan, IslamAbdelRahman, yhchiang, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D50295

Summary: Deprecate options.soft_rate_limit, which is hard to tune, with options.soft_pending_compaction_bytes_limit, which would trigger the slowdown if estimated pending compaction bytes exceeds the threshold. The hope is to make it more striaght-forward to tune.

Test Plan: Modify DBTest.SoftLimit to cover options.soft_pending_compaction_bytes_limit instead; run all unit tests.

Reviewers: IslamAbdelRahman, yhchiang, rven, kradhakrishnan, igor, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51117

Summary: Introduce a compaction picking priority that picks files who contains the oldest rows to compact. This is a mode that slightly improves write amplification for random update cases.

Test Plan: Add a unit test and run it in valgrind too.

Reviewers: yhchiang, anthony, IslamAbdelRahman, rven, kradhakrishnan, MarkCallaghan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51459

Summary: Now in benchmark "uncompress" in db_bench, we get size from compressed stream for all other compression types except Snappy, where we allocate memory based on parameter. Change it to match to behavior of other compression types.

Test Plan: Run ./db_bench --benchmarks=uncompress with snappy and other compression types.

Reviewers: yhchiang, kradhakrishnan, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51681

Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51717

Summary:
D51183 was reverted due to breaking the LITE build.

This diff is the same as D51183 but with a fix for the LITE BUILD(D51693)

Test Plan: run all unit tests

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51711

Summary:
Fixing a valgrind failure in DBTestUniversalCompaction
in the IncreaseUniversalCompactionNumLevels test. Using
SpecialSkipList with 10 rows per file.

Test Plan: Run valgrind and functional tests.

Reviewers: anthony, yhchiang, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51705

This reverts commit ec704aaf for it broke RocksDB LITE build.

Summary:
D50475 enables using SST files for transaction write-conflict checking.  In order for this to work, we need to make sure not to compact out SingleDeletes when there is an earlier transaction snapshot(D50295).  If there is a long-held snapshot, this could reduce the benefit of the SingleDelete optimization.

This diff allows Transactions to mark snapshots as being used for write-conflict checking.  Then, during compaction, we will be able to optimize SingleDeletes better in the future.

This diff adds a flag to SnapshotImpl which is used by Transactions.  This diff also passes the earliest write-conflict snapshot's sequence number to CompactionIterator.  This diff does not actually change Compaction (after this diff is pushed, D50295 will be able to use this information).

Test Plan: no behavior change, ran existing tests

Reviewers: rven, kradhakrishnan, yhchiang, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51183

Summary: DBTest.DynamicCompactionOptions ocasionally fails during valgrind run. We sent a sleeping task to block compaction thread pool but we don't wait it to run.

Test Plan: Run the test multiple times in an environment which can cause failure.

Reviewers: rven, kradhakrishnan, igor, IslamAbdelRahman, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51687

This reverts commit 2fa3ed51. It breaks RocksDB lite build

Summary:
This patch fix a race condition in persisting options which will cause a crash when:

* Thread A obtain cf options and start to persist options based on that cf options.
* Thread B kicks in and finish DropColumnFamily and delete cf_handle.
* Thread A wakes up and tries to finish the persisting options and crashes.

Test Plan: Add a test in column_family_test that can reproduce the crash

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51609

Summary:
Several tests in db_compaction_test are failing with aborts in
valgrind. These are LevelCompactionThirdPath, LevelCompactionPathUse and
CompressLevelCompaction. We now use the SpecialSkipListFactory to make
them more deterministic

Test Plan: valgrind

Reviewers: anthony, yhchiang, kradhakrishnan, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51663

Summary: After the skip list optimization, ColumnFamilyTest.DifferentWriteBufferSizes can occasionally fail with flush triggering of column family 3. Insert more data to it to make sure flush will trigger.

Test Plan: Run it multiple times with both of jemaloc on and off and see it always passes. (Without thd commit the run with jemalloc fails with chance of about one in two)

Reviewers: rven, yhchiang, IslamAbdelRahman, anthony, kradhakrishnan, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51645

Summary:
db_universal_compaction_test is still failing because of
UniversalCompactionNumLevels/DBTestUniversalCompaction.UniversalCompactionSecondPathRatio/0

https://travis-ci.org/facebook/rocksdb/jobs/94949919

Use same approach to fix other tests to fix this test

Test Plan: Run ./db_universal_compaction_test on mac and make sure all the tests pass

Reviewers: kradhakrishnan, yhchiang, rven, anthony, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51591

Summary: Skip list now cannot estimate memory across allocators
consistently and hence triggers flush at different time. This breaks certain
unit tests.

The fix is to adopt key count instead of size for flush.

Test Plan: Ran test on dev box and mac (where it used to fail)

Reviewers: sdong

CC: leveldb@

Task ID: #9273334

Blame Rev:

Summary:
Fixes T8781168.

Added a new function EnableAutoCompactions in db.h to be publicly
avialable.  This allows compaction to be re-enabled after disabling it via
SetOptions

Refactored code to set the dbptr earlier on in TransactionDB::Open and DB::Open
Temporarily disable auto_compaction in TransactionDB::Open until dbptr is set to
prevent race condition.

Test Plan:
Ran make all check

verified fix on myrocks side:
was able to reproduce the seg fault with
../tools/mysqltest.sh --mem --force rocksdb.drop_table

method was to manually sleep the thread after DB::Open but before TransactionDB ptr was
assigned in transaction_db_impl.cc:
  DB::Open(db_options, dbname, column_families_copy, handles, &db);
  clock_t goal = (60000 * 10) + clock();
  while (goal > clock());
  ...dbptr(aka rdb) gets assigned below

verified my changes fixed the issue.

Also added unit test 'ToggleAutoCompaction' in transaction_test.cc

Reviewers: hermanlee4, anthony

Reviewed By: anthony

Subscribers: alex, dhruba

Differential Revision: https://reviews.facebook.net/D51147

Summary: Fix incorrect merge in db/db_compaction_test.cc

Test Plan: db_compaction_test

Reviewers: igor, sdong, anthony, IslamAbdelRahman, rven, kradhakrishnan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51531

Summary: Make DBCompactionTestWithParam::CompactionTrigger more deterministic

Test Plan: ./db_compaction_test

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51507

Summary: Verifiction condition of DBTest.SuggestCompactRangeTest is too strict. Based on key distribution, we might have more small files in last level. Not check number of files in the last level.

Test Plan: Run DBTest.SuggestCompactRangeTest with both of jemalloc on and off.

Reviewers: rven, IslamAbdelRahman, yhchiang, kradhakrishnan, igor, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51501

Summary: DBTest.DynamicCompactionOptions sometimes fails the assert but I can't repro it locally. Make it more deterministic and readable and see whether the problem is still there.

Test Plan: Run tht test and make sure it passes

Reviewers: kradhakrishnan, yhchiang, igor, rven, IslamAbdelRahman, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51309

Summary: DBCompactionTestWithParam.CompactionTrigger fails in non-jemalloc build, after the skip list memtable change. Fix it by making mem table flush trigger by number of entries.

Test Plan: Run the test using both of jemalloc and non-jemalloc build.

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, igor, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51471

Summary: With recent commit 33e0c938, db iterator skips perf context counter internal_key_skipped_count when blindly issuing internal Next(). Now increment the counter by one when issuing this Next()

Test Plan: Run all existing tests

Reviewers: rven, yhchiang, IslamAbdelRahman, kradhakrishnan, igor, anthony

Reviewed By: anthony

Subscribers: yoshinorim, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51465

Summary: fix clang build

Test Plan: build

Reviewers: IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51453

Summary: DBTest.SuggestCompactRangeTest fails for the case when jemalloc is disabled, including ASAN and valgrind builds. It is caused by the improvement of skip list, which allocates different size of nodes for a new records. Fix it by using a special mem table that triggers a flush by number of entries. In that way the behavior will be consistent for all allocators.

Test Plan: Run the test with both of DISABLE_JEMALLOC=1 and 0

Reviewers: anthony, rven, yhchiang, kradhakrishnan, igor, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51423

DB to only flush the column family with the largest memtable while option.db_write_buffer_size is hit

Summary: When option.db_write_buffer_size is hit, we currently flush all column families. Move to flush the column family with the largest active memt table instead. In this way, we can avoid too many small files in some cases.

Test Plan: Modify test DBTest.SharedWriteBuffer to work with the updated behavior

Reviewers: kradhakrishnan, yhchiang, rven, anthony, IslamAbdelRahman, igor

Reviewed By: igor

Subscribers: march, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D51291

Summary: Now DBIter::Next() always compares with current key with itself first, which is unnecessary if the last key is not a merge key. I made the change and didn't see db_iter_test fails. Want to hear whether people have any idea what I miss.

Test Plan: Run all unit tests

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D48279

Summary:
This diff completes the creation of InlineSkipList<Cmp>, which is like
SkipList<const char*, Cmp> but it always allocates the key contiguously
with the node.  This allows us to remove the pointer from the node
to the key.  As a result the memory usage of the skip list is reduced
(by 1 to sizeof(void*) bytes depending on the padding required to align
the key storage), cache locality is improved, and we halve the number
of calls to the allocator.

For skip lists whose keys are freshly-allocated const char*,
InlineSkipList is stricly preferrable to SkipList.  This diff doesn't
replace SkipList, however, because some of the use cases of SkipList in
RocksDB are either character sequences that are not allocated at the
same time as the skip list node allocation (for example
hash_linklist_rep) or have different key types (for example
write_batch_with_index).  Taking advantage of inline allocation for
those cases is left to future work.

The perf win is biggest for small values.  For single-threaded CPU-bound
(32M fillrandom operations with no WAL log) with 16 byte keys and 0 byte
values, the db_bench perf goes from ~310k ops/sec to ~410k ops/sec.  For
large values the improvement is less pronounced, but seems to be between
5% and 10% on the same configuration.

Test Plan: make check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51123

Summary:
This diff is 2/3 in a sequence that introduces a skip list optimized
for a key that is a freshly-allocated const char*.  The change is broken
into pieces to make it easier to review.  This piece removes the Key
template type, introduces the AllocateKey interface, and changes the
unit test from using uint64_t as the Key type to using pointers to an 8
byte blob.

Test Plan: unit test

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51285

Summary:
This diff is 1/3 in a sequence that introduces a skip list optimized for
a key that is a freshly-allocated const char*.  The diff is broken into
pieces to make it easier to review.  This piece only introduces the new
type by copying the existing SkipList, with mechanical naming changes
and reformatting.

Test Plan: new unit test

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D51279

* conversion from 'size_t' to 'type', by add static_cast

Tested:
* by build solution on Windows, Linux locally,
* run tests
* build CI system successful

Summary: DBTest.DynamicLevelCompressionPerLevel2 sometimes fails during valgrind runs.  This causes our valgrind tests to fail.  Not sure what the best fix is for this test, but hopefully this simple change is sufficient.

Test Plan: run test

Reviewers: sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51111

Summary:
Provide an API for compaction filter to specify that it needs
to be applied even if there are snapshots.

Test Plan: DBTestCompactionFilter.CompactionFilterIgnoreSnapshot

Reviewers: yhchiang, IslamAbdelRahman, sdong, anthony

Reviewed By: anthony

Subscribers: yoshinorim, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D51087